System for coupling a piston for a hydraulic pump motor

ABSTRACT

A system ( 300 ) for coupling a piston for a hydraulic pump motor is provided for a hydraulic pump motor which includes a central rotor ( 3 ) of a pump motor which houses a hydraulic cylinder ( 14 ) inside of which a hydraulic piston ( 13 ) moves in translation and can push a tappet ( 18 ) guided by a hydraulic piston guided in translation by a tappet guide ( 19 ), the system ( 300 ) including a connection shaft ( 301 ) integral by a first end of the tappet ( 18 ) guided by a hydraulic piston and traversing the hydraulic piston ( 13 ) in the direction of its length via an orifice ( 307 ) of the connection shaft whereas a retention spring ( 304 ) is supported on the connection shaft ( 301 ) in the vicinity of a second end for maintaining this piston ( 13 ) in contact with the tappet ( 18 ) guided by the hydraulic piston.

The present invention relates to a system for coupling a piston for a hydraulic pump motor which constitutes an improvement of the hydraulic pump motor constituting subject matter of the French patent application No. 3001775 dated 22 May 2013 of the applicant.

The hydraulic pump motor constituting subject matter of said application comprises a central rotor for a pump motor inside of which hydraulic cylinders are arranged in which a hydraulic piston can move when this central rotor rotates relative to the housing of the pump motor. In this case these pistons can push a tappet guided by the hydraulic piston or can be pushed by the latter, which tappet is itself guided in translation by a tappet guide arranged radially or tangentially in the central rotor of the pump motor.

Note in the patent application No. 3001775 that the hydraulic pump motor comprises a tangential arm of which one of its ends is articulated in the central rotor of the pump motor whereas its other end comprises a support face for the tangential arm on the tappet which can exert a force on a line of tappet action on the tangential arm which comprises the tappet guided by the hydraulic piston, the direction of which force is approximately tangential to the axis of rotation of this arm.

Moreover, the hydraulic pump motor comprises a peripheral rotor of a pump motor constituted by a cylindrical casing of the peripheral rotor which can rotate in a peripheral rotor stator which is directly or indirectly integral with the housing of the pump motor, which central rotor of the pump motor is entirely or partly housed inside the peripheral rotor.

Note that the tangential arm comprises anti-friction means on its face located opposite the support face of the tangential arm on the tappet which means is supported on the inner surface of the cylindrical casing of the peripheral rotor.

Note that the antifriction means can be constituted by an anti-friction roller of the tangential arm which can roll on the one hand on a rolling track of the tangential arm which comprises the tangential arm on its face located opposite the support face of the tangential arm on the tappet and on the other hand on a rolling track of the peripheral rotor which comprises the inner surface of the cylindrical casing of the peripheral rotor.

The application precisely states that the anti-friction roller of the tangential arm is limited in its movement simultaneously relative to the rolling track of the tangential arm and relative to the rolling track of the peripheral rotor by roller racks of the tangential arm which comprises the rolling track of the tangential arm and by a rolling crown of the peripheral rotor which comprises the rolling track of the peripheral rotor, which tracks and which crown simultaneously cooperate with at least one roller pinion which comprises this roller.

Given this disclosed background, it is determined that the application No. 3001775 does not provide anything which prevents the hydraulic pistons from moving apart or separating in the longitudinal translation of the tappet guided by the hydraulic piston with which they cooperate.

Moreover, this application does not present any solution which guarantees that the support face of the tangential arm on the tappet remains in good permanent contact with the line of action of the tappet on the tangential arm with which it cooperates. The result of this is that the hydraulic pump motor constituting the subject matter of the present application could prove to be noisy at the moment at which it is put in motion or is stopped, or when the pressure prevailing in the chamber formed by the hydraulic cylinders with the hydraulic piston with which they cooperate is insufficient.

Therefore, in order to prevent these risks and to improve the pump motor according to the application No. 3001775 the system for the coupling of a piston for a hydraulic pump motor according to the invention allows, as a function of its method of realization:

-   -   The coupling of the hydraulic pistons of this pump motor to the         tappet guided by the hydraulic piston with which they cooperate.     -   The maintaining of the support face of the tangential arm on the         tappet always in contact with the line of action of the tappet         on the tangential arm with which it cooperates.

Moreover, the system for coupling the piston for the hydraulic pump motor according to the invention is provided to be integrated in the pump motor according to the application No. 3001775 without jeopardizing the feasibility of this pump motor at a moderate manufacturing cost price and without having to use any realization process that is complex or uses expensive material.

It is understood that aside from its application in the pump motor according to the patent application No. 3001775 the system for coupling a piston for a hydraulic pump motor according to the invention can be applied to any other hydraulic or pneumatic pump, motor or pump motor whose configuration advantageously permits this system to be exploited.

The other characteristics of the present invention have been described in the description and in the secondary claims directly or indirectly dependent on the main claim.

The system for coupling a piston for a hydraulic pump motor according to the present invention is provided for a hydraulic pump motor which comprises a pump motor housing in which a central rotor of a pump motor is housed and which latter houses at least one hydraulic cylinder inside of which a hydraulic piston can move in translation and can push a tappet guided by a hydraulic piston or can be pushed by the latter, which tappet is guided in translation by a tappet guide arranged in the central rotor of the pump motor whereas a tangential arm has a first end articulated in the central rotor of the pump motor and has a second end which comprises a support face of the tangential arm on the tappet which can exercise a force on a line of action of the tappet on the tangential arm which comprises a crossbar of force integral with the tappet guided by the hydraulic piston, which tangential arm furthermore comprises antifriction means on its face located opposite the support face of the tangential arm on the tappet, which means is supported on the internal surface of a cylindrical casing of the peripheral rotor which can rotate in a stator of the peripheral rotor integral with the housing of the pump motor, which central rotor of the pump motor is entirely or partially housed inside this peripheral rotor, which system comprises:

-   -   At least one connection shaft comprising a first end integral         with the tappet guided by a hydraulic piston, which shaft is         positioned in the prolongation of this tappet and traverses all         or part of the hydraulic piston in the direction of its length         via an orifice of the connection shaft;     -   At least one retention spring which is directly or indirectly         supported on the one hand on the connection shaft in the         vicinity of a second end which comprises this shaft and on the         other hand on the hydraulic piston in such a manner that this         spring tends to keep this piston in contact with the tappet         guided by the hydraulic piston in the prolongation in which this         piston is positioned.

The system for coupling a piston for a hydraulic pump motor according to the present invention comprises a support face of an arm tangential to the tappet which is kept in contact with the action line of the tappet on the tangential arm by a tappet placing spring which is directly or indirectly supported on the one hand on the tangential arm and on the other hand on the tappet guided by the hydraulic piston.

The system for coupling a piston for a hydraulic pump motor according to the present invention comprises a tappet placing spring which is constituted by at least one steel blade whose one end is integral with the tangential arm and whose other end is supported on the force traverse for placing it against the support face of the tangential arm on the tappet.

The system for coupling a piston for a hydraulic pump motor according to the present invention comprises a hydraulic piston which comprises—on the side of the tappet guided by the hydraulic piston—a ball joint for supporting the tappet on the hydraulic piston from which the orifice of the connection shaft begins, which ball joint cooperates with a ball joint for supporting the hydraulic piston on the tappet and arranged on the tappet guided by the hydraulic piston, and the connection shaft exits from this ball joint.

The system for coupling a piston for a hydraulic pump motor according to the present invention comprises a connection shaft which is housed in the orifice of the connection shaft with a play sufficient for allowing an oil to pass which lubricates the tappet support ball joint on the hydraulic piston at the level of the contact which the latter forms with the support ball joint of the hydraulic piston on the tappet.

The following description and the attached drawings given by way of non-limiting examples allow the invention to be better understood, the characteristics that it has and the advantages which it can obtain:

FIG. 1 is an exploded view of the hydraulic pump motor with a fixed or variable piston swept volume to which the system for coupling a piston for a hydraulic pump motor according to the invention is applied, which system is nevertheless not shown in this figure.

FIG. 2 is a schematic section of the system for coupling a piston for a hydraulic pump motor according to the invention whose connection shaft traverses a hydraulic piston constituted by a simple cylindrical body in the center of which the orifice of a connection shaft is arranged, which system is provided with a tappet placing spring constituted by a steel blade integral with the tangential arm.

FIGS. 3 and 4 are three-dimensional views of the system for coupling a piston for a hydraulic pump motor according to the invention and according to the configuration provided in FIG. 2.

FIG. 5 is a schematic section of the system for coupling a piston for a hydraulic pump motor according to the invention whose connection shaft traverses—via the orifice of the connection shaft with which it cooperates—a hydraulic piston equipped with the sealing device for a piston constituting subject matter of the French patent application No. 3009037 dates 23 Jul. 2013 belonging to the applicant in its improved version by the system for segment pre-torsion constituting subject matter of the French patent application No. 1461172 dated 19 Nov. 2014 also belonging to the applicant, which system is provided with a tappet placing spring constituted by a steel blade integral with the tangential arm.

FIGS. 6 and 7 are three-dimensional views of the piston coupling system for a hydraulic pump motor according to the invention and according to the configuration provided in FIG. 5.

FIG. 8 is an exploded three-dimensional view of the piston coupling system for a hydraulic pump motor according to the invention and according to the configuration provided in FIG. 5.

FIG. 9 is a three-dimensional view of the hydraulic pump motor with a fixed or variable piston swept volume without its pump motor housing and equipped with the piston coupling system for a hydraulic pump motor according to the invention and according to the configuration provided in FIGS. 2 to 4.

DESCRIPTION OF THE INVENTION

FIGS. 2 to 9 show the piston coupling system 300 for a hydraulic pump motor, various details of its components, its variants and its accessories.

The piston coupling system 300 for a hydraulic pump motor is provided for a hydraulic pump motor 1 such as shown in FIG. 1, which latter comprises a housing for a pump motor 2 in which a central rotor 3 of a pump motor is housed which comprises at least one hydraulic cylinder 14 inside of which a hydraulic piston 13 can move in translation and can push a tappet 18 guided by hydraulic piston or can be pushed by the latter, which tappet 18 is guided in translation by a tappet guide 19 arranged in the central rotor 3 of a pump motor.

The hydraulic pump motor 1 shown in FIG. 1 to which the piston coupling system for hydraulic pump motor 300 according to the invention is applied furthermore comprises a tangential arm 22 which comprises a first end articulated in the central rotor of the pump motor 3 and a second end comprising a support face for the tangential arm on tappet 23 which can exert a force on a line of tappet action on tangential arm 21 which comprises a force traverse 83 integral with the tappet 18 guided by a hydraulic piston, which tangential arm 22 furthermore comprises anti-friction means 196 on its face located opposite the support face of the tangential arm on tappet 23, which means 196 is supported on the inner surface of a cylindrical casing of peripheral rotor 32 which can rotate in a stator 65 of a peripheral rotor integral with the housing of pump motor 2, wherein the central rotor of pump motor 3 is entirely or partially housed inside this peripheral rotor 29.

As FIGS. 2 to 9 show, the piston coupling system for a hydraulic pump motor 300 according to the invention comprises at least one connection shaft 301 comprising a first end 302 integral with the tappet 18 guided by hydraulic piston, which shaft 301 is positioned in the prolongation of this tappet 18 and traverses all or part of the hydraulic piston 13 in the direction of its length via an orifice 307 of the connection shaft.

Note that the connection shaft 301 can be placed on the tappet 18 guided by hydraulic piston by screwing, welding, adhering or by any other fixation manner. By way of non-limiting example, a longitudinal bore can be realized, for example, in the tappet 18 guided by the hydraulic piston which receives the connection shaft 301, which latter is blocked in this bore by binding and/or by adhesion.

Note in FIGS. 2, 4, 5, 7, 8 and 9 that the piston coupling system for hydraulic pump motor 300 according to the invention also comprises at least one retention spring 304 which is directly or indirectly supported on the one hand on the connection shaft 301 in the vicinity of a second end 303 which comprises this shaft 301 and on the other hand on the hydraulic piston 13 in such a manner that this spring 304 tends to keep this piston 13 in contact with the tappet 18 guided by a hydraulic piston in the prolongation of which this piston 13 is positioned.

Note that the retention spring 304 can be a corrugated or punched elastic washer, helicoidal traction or compressive spring, a blade spring or any type known to a person skilled in the art.

FIGS. 2 to 9 illustrate that the piston coupling system for hydraulic pump motor 300 according to the invention provides that the support face of the arm tangential to tappet 23 can be kept in contact with the tappet action line on tangential arm 21 by a tappet placement spring 305 which is directly or indirectly supported on the one hand on the tangential arm 22 and on the other hand on the tappet 18 guided by hydraulic piston.

Note in the same FIGS. 2 to 9 that the tappet placement spring 305 can be constituted by at least one steel blade 306 whose one end is integral with the tangential arm 22 and whose other end is supported on the force traverse 83 in order to rest against the support face of the tangential arm on tappet 23.

By way of non-limiting example, the steel blade 306 can be made integral with tangential arm 22 by screwing, riveting, welding, nesting, clipping or by any other fixation means known to a person skilled in the art.

FIGS. 2, 5 and 8 allow it to be determined that the piston coupling system for hydraulic pump motor 300 can be realized in such a manner that the hydraulic piston 13 comprises—on the side of the tappet 18 guided by the hydraulic piston—a ball joint 17 for the support of the tappet on a hydraulic piston from which the orifice 307 of the connection shaft begins, which ball joint 17 cooperates with a ball joint for the support of the hydraulic piston on tappet 20 arranged on the tappet 18 guided by hydraulic piston, and the connection shaft 301 exits from this ball joint 20 whereas these ball joints 17, 20 together form a ball joint connection.

FIGS. 2 and 5 precisely show in an illustrative manner that the connection shaft 301 can be housed in the orifice 307 of connection shaft with a play sufficient to allow an oil to pass which lubricates the support ball joint 17 of the tappet on the hydraulic piston at the level of the contact which forms the latter with the support ball joint of the hydraulic piston on tappet 20.

FUNCTIONING OF THE INVENTION

The functioning of the system for coupling a piston for a hydraulic pump motor 300 according to the invention is readily understood from viewing the FIGS. 1 to 9.

The FIGS. 2 to 4 show the system for coupling a piston for hydraulic pump motor 300 whose connection shaft 301 traverses the hydraulic piston 13 constituted according to this example by a simple cylindrical body in the center of which the orifice 307 of the connection shaft is arranged.

It can be readily deduced—in particular from FIG. 2 and also from FIG. 8 even if the configuration of the hydraulic piston 13 is different there—that the retention spring 304 tends to keep the ball joint 17 for the support of the tappet in contact on the hydraulic piston and the ball joint 20 for the support of the hydraulic piston on the tappet. Therefore, the hydraulic piston 13 and the tappet 18 guided by the hydraulic piston are made integral in longitudinal translation by the system for coupling a piston for hydraulic pump motor 300.

As a consequence, if the hydraulic pump motor 1 is stopped or if the pressure prevailing in the chamber which forms the hydraulic cylinder 14 with the hydraulic piston 13 with which it cooperates is insufficient, there cannot be a backlash between the ball joint 17 of the tappet support on the hydraulic piston and the ball joint 20 of the tappet piston on a tappet nor a risk that these ball joints 17, 20 come apart and no longer form the sought-for ball joint connection.

This guarantees the safety and the working silence of the hydraulic pump motor 1.

It will be understood—particularly by observing the FIGS. 2, 5 and 8—that the lubrication of the ball joint for the support of the tappet on hydraulic piston 17 at the level of the contact which it forms with the ball joint 20 for the support of the hydraulic piston on the tappet is assured by supplying oil under pressure at the level of the play left between the connection shaft 301 and the orifice 307 of the connection shaft in which this shaft 301 is housed. The circulation of this oil is assured by the elevated pressure prevailing in the hydraulic cylinder 14 to which are added micromovements caused by the ball joint 17 for the support of the tappet on the hydraulic piston relative to the ball joint 20 for the support of the hydraulic piston on a tappet. This particular configuration allows very small quantities of oil to be inserted between these ball joints 17, 20 in such a manner as to lubricate the latter.

Note in FIGS. 2 to 9 the steel blade 306 constituting the tappet placement spring 305. This blade 306 realizes—in cooperation with the connection shaft 301 and with the retention spring 304—a unit of pieces integral in their movement which unit includes the tangential arm 22, the tappet 18 guided by hydraulic piston, and the hydraulic piston 13.

This unit contributes to the safety and to the working operation of the hydraulic pump motor 1 following and as a complement of that which is brought about by the return spring of tangential arm 25 such as described in the patent application No. 3001775 dated 22 May 2013 relative to this motor pump 1 belonging to the applicant, which spring 25 places the anti-friction roller of tangential arm 28 of the hydraulic pump motor 1 on the inner surface of the cylindrical casing of peripheral rotor 32 of this pump motor 1.

FIGS. 5 to 8 show a variant of the hydraulic piston 13 according to which this piston 13 is equipped with the piston sealing device 101 constituting subject matter of the patent application No. 3009037 belonging to the applicant in its version improved by the pre-torsion system of segment 121 constituting subject matter of the patent application No. 1461172, which also belongs to the applicant.

It can be seen from these figures that the connection shaft 301 advantageously realizes the inter-skirt mechanical connection 107 presented in the patent application No. 3009037. It is determined there that the fixed skirt 105 and the sliding skirt 106 find their place around this shaft 301 and retain their original function without any change.

It can be seen in FIGS. 5, 7 and 8 that the retention spring 304 plays the part of the sliding skirt spring 116 as provided in the patent application No. 3009037 in addition to that which it contributes to the piston coupling system for the hydraulic pump motor 300 according to the invention.

Therefore, this particular configuration allows the extendable, continuous segment 109 to function as provided by the patent application No. 3009037 and to ensure an extensive seal between the hydraulic cylinder 14 and the hydraulic piston 13 while producing only low losses by friction.

The possibilities of the system for coupling a piston for a hydraulic pump motor 300 according to the invention are not limited to the applications which were just described and it should moreover be understood that the previous description was only given by way of example and that it does not limit in any way the scope of this invention which is not departed from by replacing the details of execution described by any other equivalent. 

1. A system (300) for coupling a piston for a hydraulic pump motor provided for a hydraulic pump motor (1) which comprises a pump motor housing (2) in which a central rotor (3) of a pump motor is housed and which latter houses at least one hydraulic cylinder (14) inside of which a hydraulic piston (13) can move in translation and can push a tappet (18) guided by a hydraulic piston or can be pushed by the latter, which tappet (18) is guided in translation by a tappet guide (19) arranged in the central rotor (3) of the pump motor whereas a tangential arm (22) has a first end articulated in the central rotor (3) of the pump motor and has a second end which comprises a support face of the tangential arm (23) on the tappet which can exercise a force on a line of action of the tappet on the tangential arm (21) which comprises a crossbar of force (83) integral with the tappet (18) guided by the hydraulic piston, which tangential arm (22) furthermore comprises antifriction means (196) on its face located opposite the support face of the tangential arm (23) on the tappet, which means (196) is supported on the internal surface of a cylindrical casing of a peripheral rotor (32) which can rotate in a stator (65) of the peripheral rotor integral with the housing of the pump motor (2), which central rotor (3) of the pump motor is entirely or partially housed inside this peripheral rotor (29), wherein the system (300) comprises: At least one connection shaft (301) comprising a first end (302) integral with the tappet (18) guided by a hydraulic piston, which shaft (301) is positioned in the prolongation of this tappet (18) and traverses all or part of the hydraulic piston (13) in the direction of its length via an orifice (307) of the connection shaft; At least one retention spring (304) which is directly or indirectly supported on the one hand on the connection shaft (301) in the vicinity of a second end (303) which comprises this shaft (301) and on the other hand on the hydraulic piston (13) in such a manner that this spring (304) tends to keep this piston (13) in contact with the tappet (18) guided by the hydraulic piston in the prolongation in which this piston (13) is positioned.
 2. The system for coupling a piston according to claim 1, wherein the support face of the arm tangential to the tappet (23) is kept in contact with the action line of the tappet on the tangential arm (21) by a tappet placement spring (305) which is directly or indirectly supported on the one hand on the tangential arm (22) and on the other hand on the tappet (18) guided by the hydraulic piston.
 3. The system for coupling a piston according to claim 2, wherein the tappet placing spring (305) is constituted by at least one steel blade (306) whose one end is integral with the tangential arm (22) and whose other end is supported on the force traverse (83) for placing it against the support face of the tangential arm on the tappet (23).
 4. The system for coupling a piston according to claim 1, wherein the hydraulic piston (13) comprises—on the side of the tappet (18) guided by the hydraulic piston—a ball joint (17) for supporting the tappet on the hydraulic piston from which the orifice (307) of the connection shaft begins, which ball joint (17) cooperates with a ball joint (20) for supporting the hydraulic piston on the tappet and arranged on the tappet (18) guided by the hydraulic piston, and that the connection shaft (301) exits from this ball joint (20).
 5. The system for coupling a piston according to claim 4, wherein the connection shaft (301) is housed in the orifice (307) of the connection shaft with a play sufficient for allowing an oil to pass which lubricates the tappet support ball joint (17) on the hydraulic piston at the level of the contact which the latter forms with the support ball joint (20) of the hydraulic piston on the tappet. 